Nuclear localization of the C2H2 zinc finger protein Msn2p is regulated by stress and protein kinase A activity.
Msn2p and the partially redundant factor Msn4p are key regulators of stress-responsive gene expression in Saccharomyces cerevisiae. They are required for the transcription of a number of genes coding for proteins with stress-protective functions. Both Msn2p and Msn4p are Cys2His2 zinc finger proteins and bind to the stress response element (STRE). In vivo footprinting studies show that the occupation of STREs is enhanced in stressed cells and dependent on the presence of Msn2p and Msn4p. Both factors accumulate in the nucleus under stress conditions, such as heat shock, osmotic stress, carbon-source starvation, and in the presence of ethanol or sorbate. Stress-induced nuclear localization was found to be rapid, reversible, and independent of protein synthesis. Nuclear localization of Msn2p and Msn4p was shown to be correlated inversely to cAMP levels and protein kinase A (PKA) activity. A region with significant homologies shared between Msn2p and Msn4p is sufficient to confer stress-regulated localization to a SV40-NLS-GFP fusion protein. Serine to alanine or aspartate substitutions in a conserved PKA consensus site abolished cAMP-driven nuclear export and cytoplasmic localization in unstressed cells. We propose stress and cAMP-regulated intracellular localization of Msn2p to be a key step in STRE-dependent transcription and in the general stress response.
Görner
W
W
Vienna Biocenter, Institut für Biochemie und Molekulare Zellbiologie der Universität Wien and Ludwig Boltzmann-Forschungsstelle für Biochemie, A-1030 Wien, Austria.
Durchschlag
E
E
Martinez-Pastor
M T
MT
Estruch
F
F
Ammerer
G
G
Hamilton
B
B
Ruis
H
H
Schüller
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001692:Biological Transport / Q000187:drug effects; D002451:Cell Compartmentation / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003545:Cysteine; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006639:Histidine; D008969:Molecular Sequence Data; D011485:Protein Binding; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D016335:Zinc Fingers
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D006639:Histidine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D003545:Cysteine